He soon found himself in debtor's prison, but made himself popular by running errands for the guards. He was able to scrape together enough to buy his freedom. In prison he met a prostitute named Molly, who got him involved with her gang of thieves and whores. He became an expert in the underworld, serving as a pimp and a fence. He lived with Molly as her husband, even though both were already married, and served as her pimp.
Wild eventually got a job as a deputy for notoriously corrupt "Under-Marshall" Charles Hitchen, who routinely extorted money and goods, enriching himself in his position. Unfortunately this was normal at the time. London had no effective police force and a population of about 70,000 - huge for the early 1700s - and crime was on the rise. London was crawling with unemployed soldiers after the War of the Spanish Succession, which made matters worse. Wild served under Hitchen, but continued to fence goods and act as a pimp for Molly and several other prostitutes.
Eventually, Wild realized he could do better on his own - away from both Molly and Hitchen. Like a true jackass, he cut off Molly's ear to mark her as a prostitute. He set up an office, called himself Hitchen's "deputy" even though he wasn't, and wore a sword despite the fact that he did not have "gentleman" status (which was illegal).
Nevertheless, the city's fear of crime allowed him to operate as a thief-taker. He became wildly popular as he appeared to be successful at curbing crime (he sent some 60 thieves to the gallows). In truth, he specialized in having items stolen, waiting for the theft to be reported, then "discovering" the goods and returning them for a reward. If a scapegoat was needed, Wild would offer up a member of a rival gang or one of his own gang members who had crossed him. He fenced goods for them and kept the majority of profits for himself, amassing a decent pile of wealth. If he came into possession of stolen goods that would allow him to blackmail someone - such as finding a personal belonging in a whorehouse - he would often put out an advertisement in one of the many news-sheets of London, with the blackmail implied.
He became so popular that the Privy Council that advised the king asked for his input on new ways of controlling crime. Near-jackass that he was, Wild advised that the reward for capturing a thief be increased by 300 percent. Obviously, this was to his benefit and he continued to enrich himself.
When he'd tackle another gang, he would make sure the news-sheets knew about his heroics. But while appearing to be acting for the public good, Wild was just engaging in gang wars disguised as law enforcement. He soon controlled London's largest crime ring, one of the first we can consider "organized crime" in the modern sense.
Things began to go badly when he tangled with a former associate who had struck out on his own - Jack Sheppard. He was handsome, well-liked, and seen as something of a Robin Hood-type by the apprentices and cockney folk of London. He was also known for non-violence, which was probably the cause of his falling-out with Wild in the first place. Wild had him arrested, but he escaped. He was arrested again, and escaped. The news-sheets had a field day with this. Eventually Wild got Sheppard's wife so drunk she betrayed his secrets, and he was arrested again - and escaped again. This made Wild look bad in the press, and Sheppard's supporters began to grumble about Wild's apparent (and actual) hypocrisy.
West arrested a partner of Sheppard's named Blake. At trial, Blake begged to be transported to the colonies instead of facing execution, but Wild blocked the request. In a rage, Blake managed to launch himself at Wild and slit his throat. He survived, but was laid low for quite some time. Blake was executed.
Meanwhile, Sheppard was captured again, wrapped in 300 pounds of chain, and was kept under watch. He received visits from members of the gentry and public sentiment was with him, due to his ethos of non-violent thievery. Nevertheless, he too was executed, but Wild did not attend because he was still convalescing from his throat wound.
Soon after he recovered, Wild staged a violent jailbreak to free one of his thieves. This went badly, public sentiment turned against him, and he was sought by the authorities. He was sent to Newgate prison but continued to run his empire from there. He was brought to trial for the violent jailbreak and for stealing jewels from the Knights of the Garter. When it was obvious that the public had turned against him, Wild's former accomplices began giving evidence against him. He was sentenced to death. Unmanned, he broke down and begged for his life, but the court was impassive. In prison, he developed gout, was in constant pain from it, and lapsed into complete insanity. On the day of his execution he tried to commit suicide by drinking laudanum, but threw it all up and went into a coma. He was hanged anyway, still in the coma, at one of the largest public hangings in London. The same public that sang his praises earlier now cheered his death. Tickets were even sold for the best views of the hanging.
His body was buried, in secret, next to his third wife. But later in the century, when autopsies were being conducted on famous criminals, doctors dug up his body and studied it. His skeleton is still on display at the Hunterian Museum.
Wild captured the attention of writers such as Daniel Defoe, who wrote an account of his life, and was the inspiration for Peachum in John Gray's The Beggar's Opera (Sheppard is represented by Macheath, who would live on the 20th century as the inspiration for Bobby Darin's "Mack the Knife").
So, for leaving his wife and son, abusing his legal authority, betraying the public trust, cutting off Molly's ear when he was done with her, turning on his former friends and associates, bungling a jailbreak, misreading the public's admiration of Jack Sheppard, begging for his life when he'd ignored similar pleas from his former friend Blake, and for failing in his suicide attempt, I think we can safely say that while Wild might not have been a complete jackass, he comes pretty close, and deserves to be ranked among the Jackasses of History.